1212210100021 has 2 divisors, whose sum is σ = 1212210100022. Its totient is φ = 1212210100020.

The previous prime is 1212210100019. The next prime is 1212210100097. The reversal of 1212210100021 is 1200010122121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1091721971025 + 120488128996 = 1044855^2 + 347114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212210100021 - 2¹ = 1212210100019 is a prime.

Together with 1212210100019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1212210099974 and 1212210100010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212210100121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606105050010 + 606105050011.

It is an arithmetic number, because the mean of its divisors is an integer number (606105050011).

Almost surely, 2^{1212210100021} is an apocalyptic number.

It is an amenable number.

1212210100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212210100021 is an equidigital number, since it uses as much as digits as its factorization.

1212210100021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1212210100021 its reverse (1200010122121), we get a palindrome (2412220222142).

The spelling of 1212210100021 in words is "one trillion, two hundred twelve billion, two hundred ten million, one hundred thousand, twenty-one".